Field of the Invention
The present invention relates to a switching control circuit that controls on/off of a switching element.
Description of Related Art
In recent years, computerization of in-vehicle devices has been advanced, and demands for communication integrated circuits (ICs) are increased. However, a communication IC can be a noise source, and hence it is necessary to enforce countermeasures against noise in order to improve reliability of the in-vehicle devices.
In addition, also in electronic devices such as a personal computer and a portable device, integration and downsizing of circuits are promoted, and enforcement of countermeasures against noise has been demanded.
A switching regulator disclosed in FIG. 3 of JP-A-2006-129593 decreases the slew rate of a control signal that drives a switching element when a device susceptible to noise is turned on, so that noise generated from the switching regulator is reduced.
However, in the switching regulator disclosed in FIG. 3 of JP-A-2006-129593, when the device susceptible to noise is turned on, the control signal that drives the switching element has a fixed slew rate, and hence frequency of EMI noise due to the slew rate is concentrated on a specific frequency. In this way, a peak value of the EMI noise at the specific frequency is increased.